A fatal case of aspiration due to consumption of the hallucinogenic tryptamine derivative dipropyltryptamine (DPT)

BACKGROUND AND AIM

This case involves a 20-year-old man with prior hallucinogen-use experience, who sniffed an unknown amount of dipropyltryptamine in an apartment. Dipropyltryptamine, a hallucinogenic compound belonging to the tryptamine class is recognized for inducing effects similar to dimethyltryptamine (DMT) but with a longer duration. Ten to fifteen minutes later he experienced visual hallucinations, followed by increasing apathy. Two hours post consumption he developed abdominal pain, leading to collapse, seizure, and vomiting. Despite emergency medical resuscitation on site, transport to hospital 2.5 hours post consumption and extracorporeal life support he died 21 hours later. Relevant toxicological and morphological findings are presented.

METHODS

A serum sample was collected four hours post consumption. Autopsy was performed six days after death. Antemortem serum, as well as postmortem cardiac blood and urine were analyzed for alcohol and psychoactive drugs by systematic toxicological analyses employing gas chromatography-mass spectrometry (Maurer/Pfleger/Weber library among others), liquid chromatography-ion trap mass spectrometry (LC-MSn, Toxtyper™), and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Dipropyltryptamine was quantified by LC-MS/MS after solid-phase extraction.

RESULTS

Autopsy revealed a state after deep aspiration of gastric contents with consecutive brain edema due to oxygen deprivation. Dipropyltryptamine concentrations were approximately 210 ng/ml, 110 ng/ml and 180 ng/ml in antemortem serum, postmortem cardiac blood and urine, respectively. To the best of our knowledge, these are the first reported concentrations of dipropyltryptamine in a fatal case.

CONCLUSION

Unlike typical tryptamine overdose reports, this case did not present with agitation, hyperthermia, or tachycardia. Despite the individual's prior experience with tryptamines and the generally low toxicity associated with this class of hallucinogens, death in this case was an indirect consequence of the nasal consumption of a high dose of dipropyltryptamine.

Definition and terminology of developmental language disorders-Interdisciplinary consensus across German-speaking countries

In recent years, there have been intense international discussions about the definition and terminology of language disorders in childhood, such as those sparked by the publications of the CATALISE consortium. To address this ongoing debate, a Delphi study was conducted in German-speaking countries. This study consisted of three survey waves and involved over 400 experts from relevant disciplines. As a result, a far-reaching consensus was achieved on essential definition criteria and terminology, presented in 23 statements. The German term 'Sprachentwicklungsstörung' was endorsed to refer to children with significant deviations from typical language development that can negatively impact social interactions, educational progress, and/or social participation and do not occur together with a potentially contributing impairment. A significant deviation from typical language development was defined as a child's scores in standardized test procedures being ≥ 1.5 SD below the mean for children of the same age. The results of this Delphi study provide a proposal for a uniform use of terminology for language disorders in childhood in German-speaking countries.

Surgical navigation for guidewire placement from intraoperative fluoroscopy in orthopaedic surgery

Objective. Surgical guidewires are commonly used in placing fixation implants to stabilize fractures. Accurate positioning of these instruments is challenged by difficulties in 3D reckoning from 2D fluoroscopy. This work aims to enhance the accuracy and reduce exposure times by providing 3D navigation for guidewire placement from as little as two fluoroscopic images.Approach. Our approach combines machine learning-based segmentation with the geometric model of the imager to determine the 3D poses of guidewires. Instrument tips are encoded as individual keypoints, and the segmentation masks are processed to estimate the trajectory. Correspondence between detections in multiple views is established using the pre-calibrated system geometry, and the corresponding features are backprojected to obtain the 3D pose. Guidewire 3D directions were computed using both an analytical and an optimization-based method. The complete approach was evaluated in cadaveric specimens with respect to potential confounding effects from the imaging geometry and radiographic scene clutter due to other instruments.Main results. The detection network identified the guidewire tips within 2.2 mm and guidewire directions within 1.1°, in 2D detector coordinates. Feature correspondence rejected false detections, particularly in images with other instruments, to achieve 83% precision and 90% recall. Estimating the 3D direction via numerical optimization showed added robustness to guidewires aligned with the gantry rotation plane. Guidewire tips and directions were localized in 3D world coordinates with a median accuracy of 1.8 mm and 2.7°, respectively.Significance. The paper reports a new method for automatic 2D detection and 3D localization of guidewires from pairs of fluoroscopic images. Localized guidewires can be virtually overlaid on the patient's pre-operative 3D scan during the intervention. Accurate pose determination for multiple guidewires from two images offers to reduce radiation dose by minimizing the need for repeated imaging and provides quantitative feedback prior to implant placement.

Spontaneous healing of acute ACL ruptures: rate, prognostic factors and short-term outcome

INTRODUCTION

Anterior cruciate ligament (ACL) reconstruction is considered the first line treatment in ACL rupture. However, some patients return to high intensity sport activities and show a normal knee function without ACL reconstruction. Therefore, aim of this study was to evaluate the rate and prognostic factors of spontaneous healing in patients with ACL rupture and the short-term functional outcome.

METHODS

The rate, prognostic factors and short-term functional results of spontaneous healing in patients with ACL rupture were evaluated in 381 patients. Morphology of ACL rupture and extent of posterior tibial slope (PTS) were classified by MR- and x-ray imaging. In patients with normal knee stability in anesthesia examination and healed ACL during the arthroscopy 6 weeks after trauma ACL reconstruction was canceled. IKDC -, Tegner Activity Score, KT 1000 testing and radiological characteristics were collected 12 months postoperatively in these patients.

RESULTS

14.17% of the patients with ACL rupture showed a spontaneous healing after 6 weeks. Femoral ACL-rupture (p < 0.02) with integrity of ligament stump > 50% (p < 0.001), without bundle separation (p < 0.001) and decreased PTS (p < 0.001) was found significantly more often in patients with a spontaneous healed ACL. The average IKDC score was high at 84,63 in patients with healed ACL at 1 year follow-up, but KT 1000 testing was inferior compared to non-injured side.

CONCLUSION

Spontaneous healing of a ruptured ACL happened in 14% of the patients. Especially in low-demand patients with femoral single bundle lesions without increased posterior tibial slope delayed ACL surgery should be considered to await the possibility for potential spontaneous ACL healing.

Long-term opioid therapy and mental health comorbidity in chronic pain patients

OBJECTIVES

Evidence suggests that chronic pain patients with mental illness are more likely to receive long-term opioid treatment (LTOT) and at higher doses, but are also at increased risk for opioid-related harm. This study investigates LTOT and its relationship to mental illness in the setting of a university-based outpatient pain clinic with liaison psychiatric care.

METHODS

Retrospective analysis of chronic pain patients admitted between 2011 and 2015. After a one-year treatment period, patients with non-opioid treatment, guideline-recommended and high-dose LTOT were compared and multiple regression analysis was performed to identify predictors of higher opioid dosage.

RESULTS

Of 769 patients, 46% received LTOT (opioids >90 consecutive days), 13% at high dosage (≥120 oral morphine milligram equivalents (MME)/day). Two-thirds of all patients had mental illness. The prevalence of psychiatric diagnoses and prescription rate of psychotropic medication did not significantly differ between groups. Pain chronicity stages, antidepressants and sex significantly predicted MME/day but explained only a minor part of the variance. The association with antidepressants can be attributed to the prescription of antidepressants for analgesic purposes rather than for treating depression. No association with any other type of psychiatric disorders was observed.

CONCLUSION

This study shows that mental health comorbidity is highly prevalent but that the prescribed opioid dosage is independent of it in the clinical setting of this study. The concept of liaison psychiatric care may have essentially contributed to the "detachment" of opioid prescription and psychiatric conditions but cannot be isolated from other potentially contributing factors within this single-center observational study.

3D-2D image registration in the presence of soft-tissue deformation in image-guided transbronchial interventions

Purpose. Target localization in pulmonary interventions (e.g. transbronchial biopsy of a lung nodule) is challenged by deformable motion and may benefit from fluoroscopic overlay of the target to provide accurate guidance. We present and evaluate a 3D-2D image registration method for fluoroscopic overlay in the presence of tissue deformation using a multi-resolution/multi-scale (MRMS) framework with an objective function that drives registration primarily by soft-tissue image gradients.Methods. The MRMS method registers 3D cone-beam CT to 2D fluoroscopy without gating of respiratory phase by coarse-to-fine resampling and global-to-local rescaling about target regions-of-interest. A variation of the gradient orientation (GO) similarity metric (denotedGO') was developed to downweight bone gradients and drive registration via soft-tissue gradients. Performance was evaluated in terms of projection distance error at isocenter (PDE_iso). Phantom studies determined nominal algorithm parameters and capture range. Preclinical studies used a freshly deceased, ventilated porcine specimen to evaluate performance in the presence of real tissue deformation and a broad range of 3D-2D image mismatch.Results. Nominal algorithm parameters were identified that provided robust performance over a broad range of motion (0-20 mm), including an adaptive parameter selection technique to accommodate unknown mismatch in respiratory phase. TheGO'metric yielded median PDE_iso= 1.2 mm, compared to 6.2 mm for conventionalGO.Preclinical studies with real lung deformation demonstrated median PDE_iso= 1.3 mm with MRMS +GO'registration, compared to 2.2 mm with a conventional transform. Runtime was 26 s and can be reduced to 2.5 s given a prior registration within ∼5 mm as initialization.Conclusions. MRMS registration via soft-tissue gradients achieved accurate fluoroscopic overlay in the presence of deformable lung motion. By driving registration via soft-tissue image gradients, the method avoided false local minima presented by bones and was robust to a wide range of motion magnitude.

Sandwich Technique for Large Osteochondral Lesions of the Knee

OBJECTIVE

To evaluate whether a sandwich technique procedure for large osteochondral lesions (OCL) of the medial femur condyle reduces clinical symptoms and improves activity level as well as to assess repair tissue integration on MRI over 2 years.

DESIGN

Twenty-one patients (median age: 29 years, 18-44 years) who received matrix-associated autologous chondrocyte transplantation (MACT) combined with cancellous bone grafting at the medial femur condyle in a 1-step procedure were prospectively included. Patients were evaluated before surgery (baseline) as well as 3, 6, 12, and 24 months postoperatively, including clinical evaluation, Lysholm score, Tegner Activity Rating Scale, and MRI with Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score and a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS).

RESULTS

Seventeen patients were available for the 24-month (final) follow-up (4 dropouts). Lysholm significantly improved from 48 preoperatively stepwise to 95 at final follow-up (P < 0.05). Tegner improvement from 2.5 at baseline to 4.0 at final follow-up was not significant (P = 1.0). MOCART score improved significantly and stepwise from 65 at 3 months to 90 at 24 months (P < 0.05). Total WORMS improved from 14.5 at surgery to 7.0 after 24 months (P < 0.05). Body mass index and defect size at surgery correlated with total WORMS at final follow-up (P < 0.05) but did not correlate with clinical scores or defect filling.

CONCLUSION

MACT combined with cancellous bone grafting at the medial femoral condyle reduces symptoms continuously over 2 years. A 1-step procedure may reduce perioperative morbidity. However, despite improvements, patients' activity levels remain low, even 2 years after surgery.

Evaluation of the antiseptic activity of 5% alcoholic povidone-iodine solution using four different modes of application: a randomized open-label study

BACKGROUND

Before some invasive procedures, such as injections, surgical incision or intravascular catheter insertions, alcoholic antiseptics (e.g., alcoholic povidone-iodine [PVP-I]) are widely used to prevent infection.

AIM

This randomized, open-label study investigated the impact of mode of application (which includes both application technique and volume) on the antiseptic activity of 5% alcoholic PVP-I solution.

METHODS

Alcoholic PVP-I was administered on the backs of healthy adults using four modes of application: A, concentric circle method, 3mL; B, concentric circle method, 10 mL; C, back-and-forth friction method, 3 mL; D, back-and-forth friction method, 10 mL.

PRIMARY ENDPOINT

antiseptic activity of alcoholic PVP-I, assessed via change from baseline in log₁₀/cm² colony-forming units (CFU) count for total aerobic and facultative anaerobic bacteria. Safety was monitored.

FINDINGS

113 healthy participants were screened; 32 were randomized. Alcoholic PVP-I showed significant antiseptic activity with all modes of application (p<0.001 for each), providing an overall mean decrease from baseline in CFU count of >3 log₁₀/cm² (p<0.001). Significantly greater efficacy was seen with back-and-forth friction (modes C and D) versus concentric circles (modes A and B): covariate adjusted change in log₁₀/cm² CFU count 0.22; 90% confidence intervals: 0.07, 0.37 (p=0.017). No safety issues were observed.

CONCLUSION

Alcoholic PVP-I demonstrated high antiseptic activity for all modes of application. Greater efficacy was achieved with back-and-forth friction versus concentric circles, showing that application technique may influence antiseptic activity; these findings suggest that when comparing the efficacy of antiseptic substances (e.g., alcoholic PVP-I and alcoholic chlorhexidine [CHX]), comparable application techniques should be used.

Characteristics of pain and the burden it causes in patients with amyotrophic lateral sclerosis - a longitudinal study

OBJECTIVE

Pain currently plays a subordinate role in the clinical care of patients with ALS. We aim to examine epidemiological and clinical characteristics of pain as well as its impact throughout the disease course.

METHODS

During a longitudinal follow-up at three time points, 151 ALS patients from three German outpatient clinics completed the Brief Pain Inventory, ALS-Functional Rating Scale-Extension and ALS Depression Inventory. Analysis of variance and covariance with repeated measures were performed.

RESULTS

Pain was prevalent in 56% of the 151 patients at baseline and in 70% of the remaining 40 patients at the third survey. Of the 28 patients with pain who participated in all three surveys, about two thirds suffered from an average pain intensity corresponding to at least moderate pain on the numerical rating scale (NRS ≥ 4). Patients reported different pain qualities and localized the pain most frequently in the extremities, back and neck. Pain moderately impaired the functions of daily living. Pain intensity, pain quality and pain-related impairment did not significantly change over time. One third of the patients suffered from clinically relevant depressive symptoms. However, there was no conclusive evidence of a link between pain intensity and depressive symptoms.

CONCLUSION

Pain is frequent and constitutes an additional strain on ALS patients who have to endure a rapidly progressive and severely debilitating disease. This study contributes to better understanding of the characteristics of pain and its impact on ALS patients throughout the disease course and may thus help to more effectively address this symptom.

Lessons of the month 3: Intravenous poppers abuse: case report, management and possible complications

BACKGROUND

Poppers are nitrite-containing liquids, which are inhaled for their aphrodisiac and hallucinogenic effects. Despite some cases of severe poisonings, poppers are often perceived as harmless by consumers. Inhalation and ingestion of poppers are well known, but, according to our literature review, intravenous abuse has not been reported before.

CASE PRESENTATION

A 34-year-old man injected poppers intravenously for recreational purposes. He then suffered from dyspnoea and general discomfort. Upon arrival of emergency medical services, the patient was dyspnoeic with blue-grey skin colour and oxygen saturation was 82% on ambient air. Non-invasive ventilation was necessary, and he was transferred to the intensive care unit. Toluidine blue was administered because of a methaemoglobinaemia of 40% and methaemoglobin levels dropped to 0.4%. He was discharged home after a 24-hour observation. We additionally analysed the contents of the poppers bottle: isopropyl nitrite, isopropanol and acetone were detected. Possible complications and the treatment regarding intravenous administration of poppers are discussed.

CONCLUSION

We present the first published case of intravenous poppers abuse. Our patient suffered from methaemoglobinaemia and was rapidly discharged after treatment with toluidine blue. No specific treatment regarding the contents of the poppers bottle, apart from isopropyl nitrite, was necessary.

Does the anterolateral ligament protect the anterior cruciate ligament in the most common injury mechanisms? A human knee model study

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction still has a risk of re-rupture and persisting rotational instability. Thus, extra-articular structures such as the anterolateral ligament (ALL) are increasingly treated. The ALL however prevents the internal rotation of the tibia and it must be doubted that the ALL protects the ACL in other common injury mechanisms which primarily include tibial external rotation. In this study we aimed to evaluate which extra-articular structures support the ACL in excessive tibial internal and external rotation using a knee finite element (FE) model.

METHODS

Internal and external rotations of the tibia were applied to an FE model with anatomical ACL, posterior cruciate ligament (PCL), lateral collateral ligament (LCL), medial collateral ligament (MCL) and intact medial and lateral meniscus. Three additional anatomic structures (anterolateral ligament, popliteal tendon and posterior oblique ligament) were added to the FE model separately and then all together. The force histories within all structures were measured and determined for each case.

RESULTS

The ACL was the most loaded ligament both in tibial internal and external rotation. The ALL was the main stabilizer of the tibial internal rotation (46%) and prevented the tibial external rotation by only 3%. High forces were only observed in the LCL with tibial external rotation. The ALL reduced the load on the ACL in tibial internal rotation by 21%, in tibial external rotation only by 2%. The POL reduced the load on the ACL by 8%, the PLT by 6% in tibial internal rotation. In tibial external rotation the POL and PLT did not reduce the load on the ACL by more than 1%.

CONCLUSION

The ALL protects the ACL in injury mechanisms with tibial internal rotation but not in mechanisms with tibial external rotation. In injury mechanisms with tibial external rotation other structures that support the ACL need to be considered.

Fluoroscopic Guidance of a Surgical Robot: Pre-clinical Evaluation in Pelvic Guidewire Placement

PURPOSE

A method and prototype for a fluoroscopically-guided surgical robot is reported for assisting pelvic fracture fixation. The approach extends the compatibility of existing guidance methods with C-arms that are in mainstream use (without prior geometric calibration) using an online calibration of the C-arm geometry automated via registration to patient anatomy. We report the first preclinical studies of this method in cadaver for evaluation of geometric accuracy.

METHODS

The robot is placed over the patient within the imaging field-of-view and radiographs are acquired as the robot rotates an attached instrument. The radiographs are then used to perform an online geometric calibration via 3D-2D image registration, which solves for the intrinsic and extrinsic parameters of the C-arm imaging system with respect to the patient. The solved projective geometry is then be used to register the robot to the patient and drive the robot to planned trajectories. This method is applied to a robotic system consisting of a drill guide instrument for guidewire placement and evaluated in experiments using a cadaver specimen.

RESULTS

Robotic drill guide alignment to trajectories defined in the cadaver pelvis were accurate within 2 mm and 1° (on average) using the calibration-free approach. Conformance of trajectories within bone corridors was confirmed in cadaver by extrapolating the aligned drill guide trajectory into the cadaver pelvis.

CONCLUSION

This study demonstrates the accuracy of image-guided robotic positioning without prior calibration of the C-arm gantry, facilitating the use of surgical robots with simpler imaging devices that cannot establish or maintain an offline calibration. Future work includes testing of the system in a clinical setting with trained orthopaedic surgeons and residents.

Impairment of mitochondrial oxidative phosphorylation in skin fibroblasts of SALS and FALS patients is rescued by in vitro treatment with ROS scavengers

Amyotrophic lateral sclerosis (ALS) is a devastating, rapidly progressive, neurodegenerative disorder affecting upper and lower motor neurons. Approximately 10% of patients suffer from familial ALS (FALS) with mutations in different ubiquitously expressed genes including SOD1, C9ORF72, TARDBP, and FUS. There is compelling evidence for mitochondrial involvement in the pathogenic mechanisms of FALS and sporadic ALS (SALS), which is believed to be relevant for disease. Owing to the ubiquitous expression of relevant disease-associated genes, mitochondrial dysfunction is also detectable in peripheral patient tissue. We here report results of a detailed investigation of the functional impairment of mitochondrial oxidative phosphorylation (OXPHOS) in cultured skin fibroblasts from 23 SALS and 17 FALS patients, harboring pathogenic mutations in SOD1, C9ORF72, TARDBP and FUS. A considerable functional and structural mitochondrial impairment was detectable in fibroblasts from patients with SALS. Similarly, fibroblasts from patients with FALS, harboring pathogenic mutations in TARDBP, FUS and SOD1, showed mitochondrial defects, while fibroblasts from C9ORF72 associated FALS showed a very mild impairment detectable in mitochondrial ATP production rates only. While we could not detect alterations in the mtDNA copy number in the SALS or FALS fibroblast cultures, the impairment of OXPHOS in SALS fibroblasts and SOD1 or TARDBP FALS could be rescued by in vitro treatments with CoQ₁₀ (5 μM for 3 weeks) or Trolox (300 μM for 5 days). This underlines the role of elevated oxidative stress as a potential cause for the observed functional effects on mitochondria, which might be relevant disease modifying factors.

Fracture reduction planning and guidance in orthopaedic trauma surgery via multi-body image registration

PURPOSES

Surgical reduction of pelvic fracture is a challenging procedure, and accurate restoration of natural morphology is essential to obtaining positive functional outcome. The procedure often requires extensive preoperative planning, long fluoroscopic exposure time, and trial-and-error to achieve accurate reduction. We report a multi-body registration framework for reduction planning using preoperative CT and intraoperative guidance using routine 2D fluoroscopy that could help address such challenges.

METHOD

The framework starts with semi-automatic segmentation of fractured bone fragments in preoperative CT using continuous max-flow. For reduction planning, a multi-to-one registration is performed to register bone fragments to an adaptive template that adjusts to patient-specific bone shapes and poses. The framework further registers bone fragments to intraoperative fluoroscopy to provide 2D fluoroscopy guidance and/or 3D navigation relative to the reduction plan. The framework was investigated in three studies: (1) a simulation study of 40 CT images simulating three fracture categories (unilateral two-body, unilateral three-body, and bilateral two-body); (2) a proof-of-concept cadaver study to mimic clinical scenario; and (3) a retrospective clinical study investigating feasibility in three cases of increasing severity and accuracy requirement.

RESULTS

Segmentation of simulated pelvic fracture demonstrated Dice coefficient of 0.92±0.06. Reduction planning using the adaptive template achieved 2-3 mm and 2-3° error for the three fracture categories, significantly better than planning based on mirroring of contralateral anatomy. 3D-2D registration yielded ~2 mm and 0.5° accuracy, providing accurate guidance with respect to the preoperative reduction plan. The cadaver study and retrospective clinical study demonstrated comparable accuracy: ~0.90 Dice coefficient in segmentation, ~3 mm accuracy in reduction planning, and ~2 mm accuracy in 3D-2D registration.

CONCLUSION

The registration framework demonstrated planning and guidance accuracy within clinical requirements in both simulation and clinical feasibility studies for a broad range of fracture-dislocation patterns. Using routinely acquired preoperative CT and intraoperative fluoroscopy, the framework could improve the accuracy of pelvic fracture reduction, reduce radiation dose, and could integrate well with common clinical workflow without the need for additional navigation systems.

Rehabilitation nach Schlaganfall: Durch Gehirn-Computer-Schnittstelle vermittelte funktionelle Elektrostimulation

Eine Gehirn-Computer-Schnittstelle (BCI) in der Rehabilitation von Schlaganfallpatienten ermöglicht die Steuerung einer funktionellen Elektrostimulation (FES), um eine Muskelkontraktion in der gelähmten Extremität zum Zeitpunkt der Bewegungsintention durch Erkennung entsprechender Hirnsignale auszulösen. Es wird angenommen, dass eine genaue zeitliche Kohärenz zwischen Bewegungsintention und visuellem sowie propriozeptivem Feedback, ausgelöst durch eine reale Bewegung, neuroplastische Prozesse begünstigen und eine funktionelle Verbesserung der Parese bewirken kann. In dieser systematischen Übersichtsarbeit zu randomisierten kontrollierten Studien wurden die Datenbanken Pubmed, Scopus und Web of Science durchsucht und von 516 berücksichtigten Publikationen 13 ausgewählt, die auf 7 Studienpopulationen basierten. Ein direkter Vergleich der Studien ist durch Unterschiede im Studiendesign erschwert. Fünf Studien berichten von einer verbesserten motorischen Funktion in der BCI-FES-Gruppe, davon zeigen 3 signifikante Unterschiede zwischen der BCI-FES- und der Kontrollgruppe.

Platelet-rich plasma (PRP) as therapy for cartilage, tendon and muscle damage - German working group position statement

Purpose

Platelet rich plasma (PRP) is widely used in orthopaedics, but is still heavily debated. Therefore, a survey among the German “Working Group for Clinical Tissue Regeneration” of the German Society of Orthopaedics and Traumatology was conducted to achieve a consensus about the current therapeutical potential of PRP.

Methods

A first survey (n = 65 experts, all orthopaedic/trauma surgeons) was conducted (n = 13 questions). Following, a second round (n = 40 experts) was conducted with 31 questions to achieve consensus in 5 categories: three most common indications, PRP application, future research areas.

Results

Therapeutic PRP application was regarded as useful (89%), possibly even more important in the future (90%). Most common indications were tendon pathologies (77%), osteoarthritis (OA) (68%), muscle injuries (57%) and cartilage damage (51%). Consensus was reached in 16/31 statements. The application of PRP for early knee OA (Kellgren-Lawrence grade II) was regarded as potentially useful, as well as for acute and chronic tendinopathies. For chronic lesions (cartilage, tendons), multiple injections (2–4) were seen preferable to singular injections. However, no sufficient data exists on the time interval between the injections. Standardization of PRP preparation, application, frequency, as well as determining the range of indication is strongly recommended.

Conclusions

There is a need of further standardization of the PRP preparation methods, indication and application protocols for knee OA and other indications, which must be further evaluated in basic science studies and randomized controlled clinical trials.

Level of evidence

Consensus of expert opinion, Level V.

C-arm orbits for metal artifact avoidance (MAA) in cone-beam CT

Metal artifacts present a challenge to cone-beam CT (CBCT) image-guided surgery, obscuring visualization of metal instruments and adjacent anatomy-often in the very region of interest pertinent to the imaging/surgical tasks. We present a method to reduce the influence of metal artifacts by prospectively defining an image acquisition protocol-viz., the C-arm source-detector orbit-that mitigates metal-induced biases in the projection data. The metal artifact avoidance (MAA) method is compatible with simple mobile C-arms, does not require exact prior information on the patient or metal implants, and is consistent with 3D filtered backprojection (FBP), more advanced (e.g. polyenergetic) model-based image reconstruction (MBIR), and metal artifact reduction (MAR) post-processing methods. The MAA method consists of: (i) coarse localization of metal objects in the field-of-view (FOV) via two or more low-dose scout projection views and segmentation (e.g. a simple U-Net) in coarse backprojection; (ii) model-based prediction of metal-induced x-ray spectral shift for all source-detector vertices accessible by the imaging system (e.g. gantry rotation and tilt angles); and (iii) identification of a circular or non-circular orbit that reduces the variation in spectral shift. The method was developed, tested, and evaluated in a series of studies presenting increasing levels of complexity and realism, including digital simulations, phantom experiment, and cadaver experiment in the context of image-guided spine surgery (pedicle screw implants). The MAA method accurately predicted tilted circular and non-circular orbits that reduced the magnitude of metal artifacts in CBCT reconstructions. Realistic distributions of metal instrumentation were successfully localized (0.71 median Dice coefficient) from 2-6 low-dose scout views even in complex anatomical scenes. The MAA-predicted tilted circular orbits reduced root-mean-square error (RMSE) in 3D image reconstructions by 46%-70% and 'blooming' artifacts (apparent width of the screw shaft) by 20-45%. Non-circular orbits defined by MAA achieved a further ∼46% reduction in RMSE compared to the best (tilted) circular orbit. The MAA method presents a practical means to predict C-arm orbits that minimize spectral bias from metal instrumentation. Resulting orbits-either simple tilted circular orbits or more complex non-circular orbits that can be executed with a motorized multi-axis C-arm-exhibited substantial reduction of metal artifacts in raw CBCT reconstructions by virtue of higher fidelity projection data, which are in turn compatible with subsequent MAR post-processing and/or polyenergetic MBIR to further reduce artifacts.

Dyspnea as a Fatigue-Promoting Factor in ALS and the Role of Objective Indicators of Respiratory Impairment

CONTEXT

There is no evidence-based treatment for fatigue in amyotrophic lateral sclerosis (ALS), and identification of treatable causes determines management strategies. Although dyspnea is a key symptom of ALS and effectively treatable, it has not been sufficiently investigated whether dyspnea may be a fatigue-promoting factor.

OBJECTIVES

To determine the level of fatigue in dyspneic ALS patients and whether fatigue is promoted by dyspnea. We further evaluated the correlation of fatigue with respiratory function tests.

METHODS

About 101 dyspneic patients and 20 matched controls completed the ALS Functional Rating Scale-Extension and the Fatigue Severity Scale. Dyspneic patients additionally completed the Dyspnea-ALS Scale and the ALS Assessment Questionnaire and underwent respiratory function tests (forced vital capacity, sniff nasal inspiratory pressure, mean inspiratory and expiratory pressure with respective relaxation rates, and blood gases). Multiple regression and correlation analyses were conducted.

RESULTS

Dyspneic patients had significantly higher fatigue scores than nondyspneic patients, and their fatigue significantly affected quality of life. Dyspnea alone explained up to 24% of the variance in fatigue. No associations were observed between fatigue and respiratory function tests. Patients with noninvasive ventilation reported significantly more dyspnea and fatigue.

CONCLUSION

Fatigue is a frequent and bothersome symptom in dyspneic ALS patients. Dyspnea-related distress is, in contrast to objective indicators of respiratory impairment, a determining factor of experienced fatigue. There is an urgent need for further symptom relief beyond noninvasive ventilation. Adequate treatment of dyspnea has the potential for synergies in symptom management arising from the association between fatigue and dyspnea.

Multi-body 3D-2D registration for image-guided reduction of pelvic dislocation in orthopaedic trauma surgery

Surgical reduction of pelvic dislocation is a challenging procedure with poor long-term prognosis if reduction does not accurately restore natural morphology. The procedure often requires long fluoroscopic exposure times and trial-and-error to achieve accurate reduction. We report a method to automatically compute the target pose of dislocated bones in preoperative CT and provide 3D guidance of reduction using routine 2D fluoroscopy. A pelvic statistical shape model (SSM) and a statistical pose model (SPM) were formed from an atlas of 40 pelvic CT images. Multi-body bone segmentation was achieved by mapping the SSM to a preoperative CT via an active shape model. The target reduction pose for the dislocated bone is estimated by fitting the poses of undislocated bones to the SPM. Intraoperatively, multiple bones are registered to fluoroscopy images via 3D-2D registration to obtain 3D pose estimates from 2D images. The method was examined in three studies: (1) a simulation study of 40 CT images simulating a range of dislocation patterns; (2) a pelvic phantom study with controlled dislocation of the left innominate bone; (3) a clinical case study investigating feasibility in images acquired during pelvic reduction surgery. Experiments investigated the accuracy of registration as a function of initialization error (capture range), image quality (radiation dose and image noise), and field of view (FOV) size. The simulation study achieved target pose estimation with translational error of median 2.3 mm (1.4 mm interquartile range, IQR) and rotational error of 2.1° (1.3° IQR). 3D-2D registration yielded 0.3 mm (0.2 mm IQR) in-plane and 0.3 mm (0.2 mm IQR) out-of-plane translational error, with in-plane capture range of ±50 mm and out-of-plane capture range of ±120 mm. The phantom study demonstrated 3D-2D target registration error of 2.5 mm (1.5 mm IQR), and the method was robust over a large dose range, down to 5 [Formula: see text]Gy/frame (an order of magnitude lower than the nominal fluoroscopic dose). The clinical feasibility study demonstrated accurate registration with both preoperative and intraoperative radiographs, yielding 3.1 mm (1.0 mm IQR) projection distance error with robust performance for FOV ranging from 340 × 340 mm2 to 170 × 170 mm2 (at the image plane). The method demonstrated accurate estimation of the target reduction pose in simulation, phantom, and a clinical feasibility study for a broad range of dislocation patterns, initialization error, dose levels, and FOV size. The system provides a novel means of guidance and assessment of pelvic reduction from routinely acquired preoperative CT and intraoperative fluoroscopy. The method has the potential to reduce radiation dose by minimizing trial-and-error and to improve outcomes by guiding more accurate reduction of joint dislocations.

Sonographic and 3T-MRI-based evaluation of the tongue in ALS

A few systematic imaging studies employing ultrasound (HRUS) and magnetic resonance imaging (MRI) have suggested tongue measures to aid in diagnosis of amyotrophic lateral sclerosis (ALS). The relationship between structural tongue alterations and the ALS patients' bulbar and overall motor function has not yet been elucidated. We here thus aimed to understand how in-vivo tongue alterations relate to motor function and motor function evolution over time in ALS. Our study included 206 ALS patients and 104 age- and sex-matched controls that underwent HRUS and 3T MRI of the tongue at baseline. Sonographic measures comprised coronal tongue echointensity, area, height, width and height/width ratio, while MRI measures comprised sagittal T1 intensity, tongue area, position and shape. Imaging-derived markers were related to baseline and longitudinal bulbar and overall motor function. Baseline T1 intensity was lower in ALS patients with more severe bulbar involvement at baseline. Smaller baseline coronal (HRUS) and sagittal (MRI) tongue area, smaller coronal height (HRUS) and width (HRUS) as well as more rounded sagittal tongue shape predicated more rapid functional impairment - not only of bulbar, but also of overall motor function - in ALS. Our results suggest that in-vivo sonography und MRI tongue measures could aid as biomarkers to reflect bulbar and motor function impairment.

No association of complement mannose-binding lectin deficiency with cardiovascular disease in patients with Systemic Lupus Erythematosus

Cardiovascular (CV) morbidity is the major cause of death in patients with Systemic Lupus Erythematosus (SLE). Previous studies on mannose-binding lectin (MBL) gene polymorphisms in SLE patients suggest that low levels of complement MBL are associated with cardiovascular disease (CVD). However, as large studies on MBL deficiency based on resulting MBL plasma concentrations are lacking, the aim of our study was to analyze the association of MBL concentrations with CVD in SLE patients. Plasma MBL levels SLE patients included in the Swiss SLE Cohort Study were quantified by ELISA. Five different CV organ manifestations were documented. Of 373 included patients (85.5% female) 62 patients had at least one CV manifestation. Patients with MBL deficiency (levels below 500 ng/ml or 1000 ng/ml) had no significantly increased frequency of CVD (19.4% vs. 15.2%, P = 0.3 or 17.7% vs. 15.7%, P = 0.7). After adjustment for traditional CV risk factors, MBL levels and positive antiphospholipid serology (APL+) a significant association of CVD with age, hypertension, disease duration and APL+ was demonstrated. In our study of a large cohort of patients with SLE, we could not confirm previous studies suggesting MBL deficiency to be associated with an increased risk for CVD.